Material properties

Properties of glass: borosilicate, fused silica, soda-lime

Borosilicate glass (SCHOTT BOROFLOAT 33) has a density of 2.23 g/cm3 at 25 °C (SCHOTT) and a thermal expansion of 3.25 ×10⁻⁶ per K over 20 to 300 °C (SCHOTT), against 8.3 ×10⁻⁶ per K over 75 to 575 °F (Pilkington) for soda-lime glass and 0.55 ×10⁻⁶ per K at 20 °C to 320 °C (PMOptics) for fused silica. In the constrained-expansion estimate used on this page, a sudden 100 K step puts 26 MPa on borosilicate glass, 76.6 MPa on soda-lime glass and 4.82 MPa on fused silica; the estimate is not a break prediction.

Thermal expansion (the coefficient of thermal expansion, CTE) is the fractional change in length per kelvin of temperature change. Thermal shock is damage caused by a fast temperature change. Glass is a hard, brittle solid with no crystal structure that softens over a range of temperatures.

Space Mushroom · data checked 2 November 2026 · 11 profiles · download the data (CSV) · jump to the stress meter

How much stress does a sudden temperature change put on glass?

A sudden 100 K temperature step puts an estimated 26 MPa on borosilicate glass (SCHOTT BOROFLOAT 33), 76.6 MPa on soda-lime glass (Pilkington float glass) and 4.82 MPa on fused silica (PMOptics), using stress = E × α × ΔT / (1 − ν). Soda-lime glass therefore loads 2.9 times as fast as borosilicate glass. These are fully constrained surface estimates, not break predictions.

Single crystal

Sapphire, Kyocera EFG single crystal

▲ 473 MPa

4.73 MPa per K (range 4.41 to 5.1 from the printed ranges)
- Modulus E 470 GPa per Kyocera
- Expansion α 7.7 ×10⁻⁶ per K per Kyocera
- Poisson's ratio ν 0.18 to 0.29 per Kyocera
Crystal values depend on orientation; the estimate treats the crystal as isotropic.

Alternative record in use: thermal expansion 7 ×10⁻⁶ per K (Kyocera, temperature range: 40 to 400 °C; orientation: perpendicular to the c axis).
Single crystal

Sapphire, Crystran optical grade

250 MPa

2.5 MPa per K
- Modulus E 335 GPa per Crystran
- Expansion α 5.6 ×10⁻⁶ per K per Crystran
- Poisson's ratio ν 0.25 per Crystran
Crystal values depend on orientation; the estimate treats the crystal as isotropic.
Glass

Soda-lime glass

76.6 MPa

0.766 MPa per K
- Modulus E 72 GPa per Pilkington
- Expansion α 8.3 ×10⁻⁶ per K per Pilkington
- Poisson's ratio ν 0.22 per Pilkington
Alternative record in use: thermal expansion 9.5 ×10⁻⁶ per K (Wikipedia, temperature range: about 100 to 300 °C).
Glass

Aluminosilicate glass, Corning Gorilla Glass 2

73.7 MPa

0.737 MPa per K
- Modulus E 71.5 GPa per Corning
- Expansion α 8.14 ×10⁻⁶ per K per Corning
- Poisson's ratio ν 0.21 per Corning
Glass

Aluminosilicate glass, SCHOTT Xensation Core

50 MPa

0.5 MPa per K
- Modulus E 78 GPa per SCHOTT
- Expansion α 5 ×10⁻⁶ per K per SCHOTT
- Poisson's ratio ν 0.22 per SCHOTT
Glass

Aluminosilicate glass, Corning EAGLE XG

30.3 MPa

0.303 MPa per K
- Modulus E 73.6 GPa per Corning
- Expansion α 3.17 ×10⁻⁶ per K per Corning
- Poisson's ratio ν 0.23 per Corning
Alternative record in use: thermal expansion 3.55 ×10⁻⁶ per K (Corning, temperature range: 25 to 675 C).
Glass

Borosilicate glass

26 MPa

0.26 MPa per K
- Modulus E 64 GPa per SCHOTT
- Expansion α 3.25 ×10⁻⁶ per K per SCHOTT
- Poisson's ratio ν 0.2 per SCHOTT
Inputs come from more than one source document for this glass (see the table).
Glass fibre

AGY S-2 Glass fibre

17.8 MPa

0.178 MPa per K
- Modulus E 86.9 GPa per AGY
- Expansion α 1.6 ×10⁻⁶ per K per AGY
- Poisson's ratio ν 0.22 per AGY
Fibre values; the estimate treats the fibre as isotropic.

Alternative record in use: elastic modulus 89 to 90 GPa (a US patent).
Glass

Fused silica

4.82 MPa

0.0482 MPa per K
- Modulus E 72.7 GPa per PMOptics
- Expansion α 0.55 ×10⁻⁶ per K per PMOptics
- Poisson's ratio ν 0.17 per PMOptics
Glass-ceramic

ZERODUR glass-ceramic, Expansion Class 2

1.19 MPa at most

0.0119 MPa per K
- Modulus E 90.3 GPa per SCHOTT
- Expansion α 0.1 ×10⁻⁶ per K per SCHOTT, a guaranteed limit
- Poisson's ratio ν 0.24 per SCHOTT
Alternative record in use: thermal expansion 0.007 ×10⁻⁶ per K (SCHOTT, temperature range: 0 °C to 50 °C; basis: mean coefficient of linear thermal expansion, supplied as a tolerance 0 ± 0.007 ppm/K).
Glass

Corning ULE 7972 titania-silicate glass

0.244 MPa at most

0.00244 MPa per K
- Modulus E 67.6 GPa per Corning
- Expansion α 0.03 ×10⁻⁶ per K per Corning, a guaranteed limit
- Poisson's ratio ν 0.17 per Corning
Alternative record in use: thermal expansion 0.01 ×10⁻⁶ per K (Wikipedia, temperature range: 5 to 35 °C).
Metallic glass

Metglas 2605SA1 metallic glass

No estimate. Poisson's ratio: not found in any source we hold.
- Modulus E 110 GPa per Metglas
- Expansion α 7.6 ×10⁻⁶ per K per Metglas
- Poisson's ratio ν not found in any source we hold
Metallic glass

Metglas 2714A metallic glass

No estimate. Poisson's ratio: not found in any source we hold.
- Modulus E 100 to 110 GPa per Metglas
- Expansion α 12.7 ×10⁻⁶ per K per Metglas
- Poisson's ratio ν not found in any source we hold
Organic glass

Poly(allyl diglycol carbonate), ADC (CR-39)

No estimate. Elastic modulus and Poisson's ratio: not found in any source we hold.
- Modulus E not found in any source we hold
- Expansion α 117 ×10⁻⁶ per K per a US patent
- Poisson's ratio ν not found in any source we hold
Organic glass

Poly(methyl methacrylate), PMMA (PLEXIGLAS GS)

No estimate. Poisson's ratio: not found in any source we hold.
- Modulus E 3.3 GPa per PLEXIGLAS datasheet
- Expansion α 70 ×10⁻⁶ per K per PLEXIGLAS datasheet
- Poisson's ratio ν not found in any source we hold

Gauge full height = 350 MPa. A tile marked with a triangle is above that height; its number is still exact. The little bars on a gauge are bending strengths printed in the profile.

Bending strengths printed in the profiles, and the step at which the estimate reaches each

1. Borosilicate glass, normal conditions: 25 MPa (per SCHOTT). The estimate reaches it at 96 K.
2. Borosilicate glass, safety conditions: 7 MPa (per SCHOTT). The estimate reaches it at 27 K.
3. Soda-lime glass, annealed, mean MOR, 50% probability of breakage, 60 s load on weathered in-service glass: 41 MPa (per Pilkington). The estimate reaches it at 54 K.
4. Soda-lime glass, annealed, design stress for 0.8% breakage probability: 19 MPa (per Pilkington). The estimate reaches it at 25 K.
5. Soda-lime glass, heat-strengthened, mean MOR, 50% probability of breakage: 83 MPa (per Pilkington). The estimate reaches it at 108 K.
6. Soda-lime glass, fully tempered, mean MOR, 50% probability of breakage: 165 MPa (per Pilkington). The estimate reaches it at 215 K.
7. Aluminosilicate glass, SCHOTT Xensation Core, after chemical strengthening: greater than 800 MPa (per SCHOTT). The estimate reaches it at a step beyond 400 K (about 1600 K).
8. Sapphire, Kyocera EFG single crystal, single crystal (EFG): 690 MPa (per Kyocera). The estimate reaches it at 146 K.
9. Sapphire, Kyocera EFG single crystal, single crystal substrate or wafer: 480 to 895 MPa (per Valley Design). The estimate reaches it at 101 to 189 K.

The same estimate as a table

Quench stress estimate per glass: inputs, stress per kelvin and stress at 100 K and 200 K. Where a profile holds a second record, it has its own row.
Glass (type)	Young's modulus E, GPa	Thermal expansion α, ×10⁻⁶ per K	Poisson's ratio ν	Stress per K, MPa	At 100 K, MPa	At 200 K, MPa
Sapphire, Kyocera EFG single crystal (single crystal)	470Kyocera	7.7temperature range: 40 to 400 °C; orientation: parallel to the c axis; Kyocera	0.18 to 0.29Kyocera	4.73	473	946
Other record for Sapphire, Kyocera EFG single crystal	470Kyocera	7temperature range: 40 to 400 °C; orientation: perpendicular to the c axis; Kyocera	0.18 to 0.29Kyocera	4.3	430	860
Sapphire, Crystran optical grade (single crystal)	335Crystran	5.6temperature: not stated; orientation: parallel to the c axis; Crystran	0.25Crystran	2.5	250	500
Soda-lime glass (glass)	72Pilkington	8.3temperature range: 75 to 575 °F; Pilkington	0.22Pilkington	0.766	76.6	153
Other record for Soda-lime glass	72Pilkington	9.5temperature range: about 100 to 300 °C; Wikipedia	0.22Pilkington	0.877	87.7	175
Aluminosilicate glass, Corning Gorilla Glass 2 (glass)	71.5Corning	8.14temperature range: 0 to 300 C; Corning	0.21Corning	0.737	73.7	147
Aluminosilicate glass, SCHOTT Xensation Core (glass)	78SCHOTT	5temperature range: 20 to 300 C; SCHOTT	0.22SCHOTT	0.5	50	100
Aluminosilicate glass, Corning EAGLE XG (glass)	73.6Corning	3.17temperature range: 0 to 300 C; Corning	0.23Corning	0.303	30.3	60.6
Other record for Aluminosilicate glass, Corning EAGLE XG	73.6Corning	3.55temperature range: 25 to 675 C; Corning	0.23Corning	0.339	33.9	67.9
Borosilicate glass (glass)	64SCHOTT	3.25temperature range: 20 to 300 °C; standard: ISO 7991; SCHOTT	0.2SCHOTT	0.26	26	52
AGY S-2 Glass fibre (glass fibre)	86.9AGY	1.6temperature: -30.0 to 250 °C (-22.0 to 482 °F); basis: average, isotropic, as printed; AGY	0.22AGY	0.178	17.8	35.7
Other record for AGY S-2 Glass fibre	89 to 90a US patent	1.6temperature: -30.0 to 250 °C (-22.0 to 482 °F); basis: average, isotropic, as printed; AGY	0.22AGY	0.184	18.4	36.7
Fused silica (glass)	72.7PMOptics	0.55temperature: 20 °C to 320 °C; PMOptics	0.17PMOptics	0.0482	4.82	9.63
ZERODUR glass-ceramic, Expansion Class 2 (glass-ceramic)	90.3SCHOTT	up to 0.1temperature range: 0 °C to 50 °C; basis: mean coefficient of linear thermal expansion, supplied as a tolerance 0 ± 0.100 ppm/K; SCHOTT	0.24SCHOTT	0.0119	at most 1.19	at most 2.38
Other record for ZERODUR glass-ceramic, Expansion Class 2	90.3SCHOTT	up to 0.007temperature range: 0 °C to 50 °C; basis: mean coefficient of linear thermal expansion, supplied as a tolerance 0 ± 0.007 ppm/K; SCHOTT	0.24SCHOTT	0.000832	at most 0.0832	at most 0.166
Corning ULE 7972 titania-silicate glass (glass)	67.6Corning	up to 0.03temperature range: 5 to 35 °C; Corning	0.17Corning	0.00244	at most 0.244	at most 0.489
Other record for Corning ULE 7972 titania-silicate glass	67.6Corning	0.01temperature range: 5 to 35 °C; Wikipedia	0.17Corning	0.000814	0.0814	0.163
Metglas 2605SA1 metallic glass (metallic glass)	110Metglas	7.6temperature range: 30 to 300 °C; Metglas	not found in any source we hold	—	—	—
Metglas 2714A metallic glass (metallic glass)	100 to 110Metglas	12.7Metglas	not found in any source we hold	—	—	—
Poly(allyl diglycol carbonate), ADC (CR-39) (organic glass)	not found in any source we hold	117temperature range: not printed; state: cured polymer; a US patent	not found in any source we hold	—	—	—
Poly(methyl methacrylate), PMMA (PLEXIGLAS GS) (organic glass)	3.3PLEXIGLAS datasheet	70test standard: DIN 53752-A; temperature range: 0 to 50 degC; PLEXIGLAS datasheet	not found in any source we hold	—	—	—

The formula is the standard constrained-expansion estimate from engineering texts (general engineering knowledge, not in our data): a surface that is held flat while its temperature changes by ΔT carries a stress of E α ΔT / (1 − ν). E is in GPa and α in ×10⁻⁶ per K, so E × α × ΔT / 1000 gives MPa. Where a range is printed (Poisson's ratio for Kyocera sapphire), the table uses the midpoint and the gauge states the range. A glass with an input missing has no estimate; the page does not assume a value. Sapphire and S-2 Glass fibre are crystal and fibre values treated as isotropic. ZERODUR and ULE expansion values are supplied limits around zero, so their stresses are "at most".

What is glass made of, and how do the types differ?

Glass types differ in what is added to silica. Our profiles print borosilicate glass as Silica-boria glass: about 80% SiO2, 13% B2O3, 4% Na2O or K2O and 2-3% Al2O3 for the low-expansion laboratory type, soda-lime glass as Silica-soda-lime glass: about 72.6% SiO2, 13.9% Na2O and 8.4% CaO, with 3.9% MgO and 1.1% Al2O3 (typical sheet composition) and fused silica as SiO2, amorphous silicon dioxide (fused silica, fused quartz).

Composition of each glass type as the profile prints it. Compositions are typical examples, not specifications.
Material	Composition as printed	Source
Borosilicate glass	Silica-boria glass: about 80% SiO2, 13% B2O3, 4% Na2O or K2O and 2-3% Al2O3 for the low-expansion laboratory type	Wikipedia
Fused silica	SiO2, amorphous silicon dioxide (fused silica, fused quartz)	PMOptics
Soda-lime glass	Silica-soda-lime glass: about 72.6% SiO2, 13.9% Na2O and 8.4% CaO, with 3.9% MgO and 1.1% Al2O3 (typical sheet composition)	Continental Trade
Aluminosilicate glass	Silica-alumina network with alkali or alkaline-earth oxides (model alkali aluminosilicate: 0.25 Na2O, 0.08 Al2O3, 0.67 SiO2 in mole fraction; EAGLE XG is an alkaline-earth boro-aluminosilicate)	Corning
ULE 7972 (Corning ultra low expansion titania-silicate glass)	Titania-silicate glass: silica (SiO2) with about 7.5% titanium dioxide (TiO2) per NASA (2003); Wikipedia gives less than 10% TiO2	NASA
ZERODUR (lithium aluminium silicon oxide glass-ceramic)	Lithium aluminium silicon oxide glass-ceramic, with nanocrystals in a residual glass phase (no single formula; oxide percentages not found in any source we hold)	SCHOTT
AGY S-2 Glass fibre and S-2 glass composites	Magnesium aluminosilicate glass fibre (S-glass family): about 65 wt% SiO2, 25 wt% Al2O3 and 10 wt% MgO, with SiO2 and Al2O3 together about 90 wt%	a US patent
Metallic glass (amorphous metal ribbons)	Iron-based amorphous ribbon, nominal Fe80 Si9 B11 at % for Metglas 2605SA1 (DOE/NETL core report); cobalt-based ribbon, nominal Co66 Fe4 Ni1 B15 Si14 for Metglas 2714A (Yang et al. 1997, abstract); nickel-based brazing foil MBF20, nominal Cr 7.0, Fe 3.0, Si 4.5, B 3.2 wt %, C max 0.06 wt %, balance Ni (Metglas page)	Metglas
Poly(allyl diglycol carbonate), ADC (CR-39)	Poly(allyl diglycol carbonate), a crosslinked thermoset of the monomer diethylene glycol bis(allyl carbonate), C12H18O7 (monomer)	NASA
Poly(methyl methacrylate)	(C5H8O2)n	Safety Data Sheet:
Sapphire (single-crystal alpha-alumina)	Al2O3	Crystran

General engineering knowledge, not in our data: every glass here has silica (SiO2) as its network. Adding sodium and calcium oxides lowers the melting temperature and makes cheap window glass; adding boric oxide lowers the thermal expansion; adding alumina and alkali oxides gives the aluminosilicates used where chemical strengthening matters; leaving everything out gives fused silica, which needs the highest forming temperature.

A glass-ceramic such as ZERODUR has nanocrystals in a glass phase; a glass fibre such as AGY S-2 Glass is drawn into filaments; metallic glass, PMMA and CR-39 are glasses only in the sense of having no crystal order. They are covered under metallic glass and others.

What are the density, thermal expansion and thermal conductivity of glass?

Borosilicate glass: density 2.23 g/cm3 at 25 °C (SCHOTT), expansion 3.25 ×10⁻⁶ per K over 20 to 300 °C (SCHOTT), conductivity 1.2 W/(m·K) at 90 °C (SCHOTT). Soda-lime glass: 2.5 g/cm3 at 18 °C (Continental Trade), 8.3 ×10⁻⁶ per K over 75 to 575 °F (Pilkington), 0.937 W/(m·K) at 75 °F (Pilkington). Fused silica: 2.2 g/cm3 temperature not stated (PMOptics), 0.55 ×10⁻⁶ per K at 20 °C to 320 °C (PMOptics), 1.4 W/(m·K) temperature not stated (PMOptics).

Density, thermal expansion and thermal conductivity of glasses and related materials. Each value is one source's record, with its own temperature range and source; values are not merged.
Material	Density, g/cm3	Thermal expansion, ×10⁻⁶ per K	Thermal conductivity, W/(m·K)
Borosilicate glass	2.23temperature: 25 °C; per SCHOTT	3.25temperature range: 20 to 300 °C; standard: ISO 7991; per SCHOTT; printed as 3.25 x10^-6 K^-1	1.2temperature: 90 °C; per SCHOTT
Fused silica	2.2temperature: not stated; per PMOptics	0.55temperature: 20 °C to 320 °C; per PMOptics; printed as 5.5e-7 m/(m·°C)	1.4temperature: not stated; per PMOptics; printed as 1.4 W/(m·°C) 1.3temperature: 25 °C; basis: unless otherwise stated, values on the sheet are at 25 °C; per Corning; printed as 1.3 W/m K
Soda-lime glass	2.5temperature: 18 °C; per Continental Trade; printed as 2500 kg/m3	8.3temperature range: 75 to 575 °F; per Pilkington; printed as 8.3 x10^-6 /°C 9.5temperature range: about 100 to 300 °C; per Wikipedia; printed as 9.5 ppm/K	0.937temperature: 75 °F; per Pilkington
Aluminosilicate glass, Corning EAGLE XG	2.38temperature: 20 C; per Corning; printed as 2.38 g/cc	3.17temperature range: 0 to 300 C; per Corning; printed as 31.7 x10^-7/C 3.55temperature range: 25 to 675 C; per Corning; printed as 35.5 x10^-7/C	1.09temperature: 23 C; per Corning; printed as 0.0109 W/cm.K
Aluminosilicate glass, Corning Gorilla Glass 2	2.42basis: no temperature printed on the sheet; per Corning	8.14temperature range: 0 to 300 C; per Corning; printed as 81.4 x10^-7/C	not found in any source we hold
Aluminosilicate glass, SCHOTT Xensation Core	2.38basis: typical measured values, unstrengthened glass; per SCHOTT	5temperature range: 20 to 300 C; per SCHOTT; printed as 5 x10^-6/K	not found in any source we hold
Corning ULE 7972 titania-silicate glass	2.21temperature: 25 °C (sheet default, unless otherwise stated all values are at 25 °C); per Corning	up to 0.03temperature range: 5 to 35 °C; per Corning; printed as 30 ppb/°C 0.01temperature range: 5 to 35 °C; per Wikipedia; printed as 1e-8 /K	1.31temperature: 25 °C (sheet default); per Corning; printed as 1.31 W/(m·°C)
ZERODUR glass-ceramic, Expansion Class 2	2.53temperature: not printed in the datasheet; per SCHOTT	up to 0.007ZERODUR, Expansion Class 0 Extreme; temperature range: 0 °C to 50 °C; basis: mean coefficient of linear thermal expansion, supplied as a tolerance 0 ± 0.007 ppm/K; per SCHOTT; printed as 0.007 ppm/K up to 0.1ZERODUR, Expansion Class 2; temperature range: 0 °C to 50 °C; basis: mean coefficient of linear thermal expansion, supplied as a tolerance 0 ± 0.100 ppm/K; per SCHOTT; printed as 0.1 ppm/K	1.46temperature: 20 °C; per SCHOTT
AGY S-2 Glass fibre	2.46form: fibre; the datasheet does not name a filament, strand or roving; temperature: not stated; per AGY; printed as 2.46 g/cc	1.6temperature: -30.0 to 250 °C (-22.0 to 482 °F); basis: average, isotropic, as printed; per AGY; printed as 1.6 µm/m-°C	1.1 to 1.4temperature: not stated; per AGY; printed as 1.1 to 1.4 W/m-K
Metglas 2605SA1 metallic glass	7.18note: the datasheet says these numbers are not guaranteed; per Metglas	7.6temperature range: 30 to 300 °C; per Metglas; printed as 7.6 x10-6/°C	not found in any source we hold
Metglas 2714A metallic glass	7.59per Metglas	12.7per Metglas; printed as 12.7 ppm/°C	not found in any source we hold
Poly(allyl diglycol carbonate), ADC (CR-39)	1.317state: cured polymer; temperature: not printed; per NASA 1.32state: cured polymer; temperature: not printed; per a US patent; printed as 1.32 specific gravity (unitless) 1.143state: liquid monomer, allyl diglycol carbonate; temperature: not printed; per Wikipedia	117temperature range: not printed; state: cured polymer; per a US patent; printed as 117 µm/m/°C	not found in any source we hold
Poly(methyl methacrylate), PMMA (PLEXIGLAS GS)	1.19test standard: ISO 1183; temperature: 23 degC; humidity: 50% relative humidity; per PLEXIGLAS datasheet	70test standard: DIN 53752-A; temperature range: 0 to 50 degC; per PLEXIGLAS datasheet; printed as 0.00007 1/K	0.19test standard: DIN 52612; per PLEXIGLAS datasheet; printed as 0.19 W/(m K)
Sapphire (single-crystal alpha-alumina), all records	3.97form: single crystal, optical grade; temperature: not stated on the page; per Crystran 3.98form: single crystal, wafer or substrate; temperature: 20 °C; per Valley Design	7.7temperature range: 40 to 400 °C; orientation: parallel to the c axis; per Kyocera; printed as 7.7 ppm/K 7temperature range: 40 to 400 °C; orientation: perpendicular to the c axis; per Kyocera; printed as 7 ppm/K 5.6temperature: not stated; orientation: parallel to the c axis; per Crystran; printed as 5.6 ppm/K	42temperature: 20 °C; form: single crystal (EFG); per Kyocera 27.21temperature: 300 K; form: single crystal, optical grade; per Crystran 23temperature: 23 °C; orientation: perpendicular to the c axis; per Valley Design 25.8temperature: 24 °C; orientation: parallel to the c axis; per Valley Design

Densities printed in kg/m3 are shown in g/cm3 with the printed value beside them. Thermal expansion printed in ppm per K, ppb per °C, µm/m/°C or ×10⁻⁷ per °C is shown in ×10⁻⁶ per K. Thermal conductivity printed in W/(cm·K) is shown in W/(m·K). Conversions are multiplications by a fixed factor; nothing is rounded to a neighbouring value.

Why does borosilicate glass resist thermal shock?

Borosilicate glass resists thermal shock because its thermal expansion is low: 3.25 ×10⁻⁶ per K over 20 to 300 °C (SCHOTT) against 8.3 ×10⁻⁶ per K over 75 to 575 °F (Pilkington) for soda-lime glass. With similar stiffness, that gives 0.26 MPa of constrained stress per kelvin against 0.766 MPa for soda-lime glass, a ratio of 2.9. Fused silica builds only 0.0482 MPa per kelvin.

The stress per kelvin is the product of three profile numbers: stiffness, expansion and Poisson's ratio. For borosilicate glass the stiffness term E / (1 − ν) is 80 GPa and for soda-lime glass it is 92.3 GPa, a difference of 1.2 times. The expansion differs by 2.6 times, so expansion, not stiffness, sets the gap. Fused silica has 0.55 ×10⁻⁶ per K (PMOptics) and a stiffness term of 87.6 GPa.

ZERODUR Expansion Class 2 is supplied with a mean expansion of 0 ± 0.1 ×10⁻⁶ per K over 0 °C to 50 °C (SCHOTT), which limits the estimate to at most 0.0119 MPa per kelvin.

Expansion is not the whole story. How fast heat moves through the glass (thermal conductivity), the thickness, the shape, the edge finish and how evenly the temperature changes also decide whether a part cracks (general engineering knowledge, not in our data). The profiles hold none of those test conditions for the estimate.

What do the suppliers print as safe temperature steps?

Supplier-printed thermal shock limits next to the constrained-expansion estimate at the same step. The limits and the estimate inputs come from different documents, so agreement is a sanity check and not a validation.
Glass	Supplier rating for	Printed step, K	Source of the limit	Estimate at that step, MPa
Borosilicate glass	1 h exposure (RTD)	110	SCHOTT	28.6
Borosilicate glass	1 to 100 h exposure (RTD)	90	SCHOTT	23.4
Borosilicate glass	over 100 h exposure (RTD)	80	SCHOTT	20.8
Borosilicate glass	panel under 4 mm thick (RTS)	175	SCHOTT	45.5
Borosilicate glass	panel 4 to 6 mm thick (RTS)	160	SCHOTT	41.6
Borosilicate glass	panel 6 to 15 mm thick (RTS)	150	SCHOTT	39
Borosilicate glass	panel over 15 mm thick (RTS)	140	SCHOTT	36.4
Soda-lime glass	not-toughened glass	50	Continental Trade	38.3
Soda-lime glass	toughened glass	118	Continental Trade	90.4

For borosilicate glass, SCHOTT also prints a bending strength of 25 MPa under normal conditions and 7 MPa under safety conditions (DIN 52 292 Part 1); the estimate reaches 25 MPa at 96 K and 7 MPa at 27 K. For soda-lime glass, Pilkington prints 41 MPa as the mean modulus of rupture and 19 MPa as the design stress of annealed float glass and 165 MPa for fully tempered glass; the estimate reaches 41 MPa at 54 K. SCHOTT's thermal shock resistance (RTS) ratings of 140 to 175 K are above the 96 K at which the estimate reaches the printed bending strength, so in our reading the fully constrained estimate is the cautious one for this glass. The profiles do not hold the test basis of the supplier ratings, so the two should not be read as the same test.

What is the melting point of borosilicate glass?

Borosilicate glass has no single melting point because glass softens over a range of temperatures (general engineering knowledge, not in our data). SCHOTT prints a softening point of 815 °C, an annealing point of 560 °C and a transformation temperature of 525 °C.

Temperature points of glasses: transformation or glass transition, strain, annealing and softening points, and maximum service temperature, in °C. Kelvin values are converted by subtracting 273.15.
Material	Transformation or glass transition, °C	Strain point, °C	Annealing point, °C	Softening point, °C	Maximum service temperature, °C
Borosilicate glass	525standard: ISO 7884; per SCHOTT	not found in any source we hold	560per SCHOTT	815viscosity: 10^7.6 dPa·s; per SCHOTT	500duration: less than 10 h; per SCHOTT 450duration: 10 h or more; per SCHOTT
Fused silica	not found in any source we hold	1120temperature: not stated; per PMOptics	1215temperature: not stated; per PMOptics	1683temperature: not stated; per PMOptics	1080basis: mechanical limit as labelled on the page; per MakeItFrom
Soda-lime glass	not found in any source we hold	511standard: ASTM C336; per Pilkington	548standard: ASTM C336; per Pilkington	715standard: ASTM C338; per Pilkington	110glass kind: not toughened; per Continental Trade 150glass kind: toughened; per Continental Trade
Aluminosilicate glass, Corning EAGLE XG	not found in any source we hold	669viscosity: 10^14.5 poise; per Corning; printed as 669 C	722viscosity: 10^13 poise; per Corning; printed as 722 C	971viscosity: 10^7.6 poise; per Corning; printed as 971 C	not found in any source we hold
Aluminosilicate glass, Corning Gorilla Glass 2	not found in any source we hold	599viscosity: 10^14.7 poise; per Corning; printed as 599 C	653viscosity: 10^13.2 poise; per Corning; printed as 653 C	895viscosity: 10^7.6 poise; per Corning; printed as 895 C	not found in any source we hold
Aluminosilicate glass, SCHOTT Xensation Core	580per SCHOTT; printed as 580 C	not found in any source we hold	590viscosity: 10^13 dPas; per SCHOTT; printed as 590 C	820viscosity: 10^7.6 dPas; per SCHOTT; printed as 820 C	not found in any source we hold
Corning ULE 7972 titania-silicate glass	not found in any source we hold	890basis: as printed on the sheet, which gives 1634 °F alongside; per Corning	1000basis: as printed on the sheet, which gives 1832 °F alongside; per Corning	1490basis: printed by Corning as an estimated value, 2714 °F alongside; per Corning	800basis: printed as maximum working temperature in the AZoM table, with no condition given; per AZoM: Ultra Low
ZERODUR glass-ceramic, Expansion Class 2	not found in any source we hold	not found in any source we hold	not found in any source we hold	not found in any source we hold	600basis: maximum application temperature printed by SCHOTT for ZERODUR; per SCHOTT
AGY S-2 Glass fibre	845basis: printed on the row labelled Transformation Temperature, Tg; per AGY	766basis: strain point as printed in the features table; per AGY	816basis: annealing point as printed in the features table; per AGY	1056basis: softening point as printed; per AGY 1056basis: softening point as printed in the features table; per AGY	875atmosphere: air; per AGY 875atmosphere: inert; per AGY
Metglas 2605SA1 metallic glass	not found in any source we hold	not found in any source we hold	not found in any source we hold	not found in any source we hold	not found in any source we hold
Metglas 2714A metallic glass	not found in any source we hold	not found in any source we hold	not found in any source we hold	not found in any source we hold	90note: printed as continuous service temperature; per Metglas
Poly(allyl diglycol carbonate), ADC (CR-39)	91basis: temperature of maximum tan delta, which the source calls the glass transition; sample: commercial ADC 2 mm plate; per a US patent	not found in any source we hold	not found in any source we hold	not found in any source we hold	100duration: continuous; basis: optical use in eyeglasses; per Wikipedia
Poly(methyl methacrylate), PMMA (PLEXIGLAS GS)	not found in any source we hold	not found in any source we hold	not found in any source we hold	not found in any source we hold	80basis: permanent (long-term) use in air; no test standard given; per PLEXIGLAS datasheet; printed as 80 degC
Sapphire (single-crystal alpha-alumina), all records	not found in any source we hold	not found in any source we hold	not found in any source we hold	not found in any source we hold	not found in any source we hold

The strain, annealing and softening points are the temperatures at which the glass reaches fixed viscosities (general engineering knowledge, not in our data). Below the strain point stress relaxes only over very long times; at the annealing point it relaxes within minutes. A viscosity is shown beside a point only where the profile prints it with its power of ten.

How stiff and how strong is glass?

Soda-lime glass prints a Young's modulus of 72 GPa (Pilkington) and, for annealed float glass, a mean bending strength of 41 MPa (Pilkington). Borosilicate glass prints 64 GPa (SCHOTT) and 25 MPa under normal conditions (SCHOTT). The two strengths come from different tests, so we do not rank them.

Stiffness, Poisson's ratio, specific heat, refractive index and bending strength of glasses and related materials, with the condition of each record.
Material	Young's modulus, GPa	Poisson's ratio	Specific heat, J/(g·K)	Refractive index	Bending strength, MPa
Borosilicate glass	64standard: DIN 13316; per SCHOTT; printed as 64 kN/mm2	0.2standard: DIN 13316; per SCHOTT	0.83temperature range: 20 to 100 °C; per SCHOTT; printed as 0.83 kJ/(kg·K)	1.471wavelength: 587.6 nm; note: reference value, not guaranteed by the manufacturer; per SCHOTT; printed as 1.4714 nd (587.6 nm)	25standard: DIN 52 292 Part 1; basis: normal conditions; per SCHOTT 7standard: DIN 52 292 Part 1; basis: safety conditions; per SCHOTT
Fused silica	72.7temperature: not stated; per PMOptics	0.17temperature: not stated; per PMOptics	0.72temperature: not stated; per MakeItFrom; printed as 720 J/(kg·K)	1.457wavelength: 0.633 µm; sample: typical synthetic fused silica; temperature: not stated; per PMOptics 1.45wavelength: 1.064 µm; sample: typical synthetic fused silica; temperature: not stated; per PMOptics 1.457wavelength: 632.8 nm; extinction coefficient: 0; sample: typical sample of SiO2; temperature: not stated; per Refractive Index of	not found in any source we hold
Soda-lime glass	72basis: float glass, Pilkington North America; per Pilkington	0.22basis: float glass, Pilkington North America; per Pilkington; printed as 0.22 -	0.88temperature: 75 °F; per Pilkington; printed as 0.88 kJ/(kg·K)	1.523wavelength: sodium D line (printed as 0.5893 m); per Pilkington; printed as 1.523 -	41glass kind: annealed; basis: mean MOR, 50% probability of breakage, 60 s load on weathered in-service glass; per Pilkington 19glass kind: annealed; basis: design stress for 0.8% breakage probability; per Pilkington 83glass kind: heat-strengthened; basis: mean MOR, 50% probability of breakage; per Pilkington 165glass kind: fully tempered; basis: mean MOR, 50% probability of breakage; per Pilkington
Aluminosilicate glass, Corning EAGLE XG	73.6per Corning	0.23per Corning; printed as 0.23 -	0.768temperature: 23 C; per Corning; printed as 0.768 J/(g.K)	1.51wavelength: 589.3 nm; per Corning; printed as 1.5099 -	not found in any source we hold
Aluminosilicate glass, Corning Gorilla Glass 2	71.5per Corning	0.21per Corning; printed as 0.21 -	not found in any source we hold	1.5wavelength: 590 nm; per Corning; printed as 1.5 -	not found in any source we hold
Aluminosilicate glass, SCHOTT Xensation Core	78basis: typical measured values, unstrengthened glass; per SCHOTT; printed as 78 kN/mm2	0.22per SCHOTT; printed as 0.22 -	not found in any source we hold	1.511wavelength: 595 nm; per SCHOTT; printed as 1.511 -	800bound: printed as greater than 800 MPa; state: after chemical strengthening; per SCHOTT
Corning ULE 7972 titania-silicate glass	67.6temperature: 25 °C (sheet default); per Corning	0.17temperature: 25 °C (sheet default); per Corning; printed as 0.17 -	0.767temperature: 25 °C (sheet default; the sheet gives a mean value without a temperature range); per Corning; printed as 767 J/(kg·°C)	1.483wavelength: 589 nm (nD); material: nominal CTE material, as printed; per Corning; printed as 1.4828 -	not found in any source we hold
ZERODUR glass-ceramic, Expansion Class 2	90.3temperature: 20 °C; basis: mean value; per SCHOTT	0.24temperature: not printed in the table; per SCHOTT; printed as 0.24 -	0.8temperature: 20 °C; per SCHOTT	1.542basis: nd as printed in the datasheet; the wavelength is not restated in the table; per SCHOTT; printed as 1.5424 -	not found in any source we hold
AGY S-2 Glass fibre	86.9form: fibre; form not stated; temperature: not stated; per AGY 89 to 90basis: typical value quoted as relevant data in a patent background; form and test not stated; per a US patent	0.22temperature: not stated; per AGY; printed as 0.22 -	0.737temperature: 23.0 °C (73.4 °F); per AGY; printed as 0.737 J/g-°C 0.935temperature: 200 °C (392 °F); per AGY; printed as 0.935 J/g-°C	1.521wavelength: not stated; per AGY; printed as 1.521 -	not found in any source we hold
Metglas 2605SA1 metallic glass	110note: the datasheet says these numbers are not guaranteed; per Metglas	not found in any source we hold	not found in any source we hold	not found in any source we hold	not found in any source we hold
Metglas 2714A metallic glass	100 to 110per Metglas	not found in any source we hold	not found in any source we hold	not found in any source we hold	not found in any source we hold
Poly(allyl diglycol carbonate), ADC (CR-39)	not found in any source we hold	not found in any source we hold	not found in any source we hold	1.498wavelength: not printed; state: cured polymer; per a US patent; printed as 1.498 unitless 1.45state: liquid monomer; temperature: not printed; per Wikipedia; printed as 1.45 unitless	not found in any source we hold
Poly(methyl methacrylate), PMMA (PLEXIGLAS GS)	3.3test standard: ISO 527-2/1B/1; temperature: 23 degC; humidity: 50% relative humidity; per PLEXIGLAS datasheet; printed as 3300 MPa	not found in any source we hold	not found in any source we hold	1.491test standard: ISO 489; temperature: 20 degC; wavelength: sodium D line (nD); per PLEXIGLAS datasheet	not found in any source we hold
Sapphire (single-crystal alpha-alumina), all records	470form: single crystal (EFG); temperature: not stated; per Kyocera 335form: single crystal, optical grade; temperature: not stated; per Crystran 335 to 435form: single crystal substrate or wafer; per Valley Design	0.18 to 0.29form: single crystal (EFG); per Kyocera; printed as 0.18 to 0.29 - 0.25form: single crystal, optical grade; per Crystran; printed as 0.25 -	0.75temperature: not stated; per Kyocera 0.763temperature: 293 K; per Crystran; printed as 763 J/(kg·K)	1.768wavelength: 589 nm; ray: ordinary (No); per Kyocera; printed as 1.768 - 1.76wavelength: 589 nm; ray: extraordinary (Ne); per Kyocera; printed as 1.76 - 1.754wavelength: 1.06 µm; ray: ordinary (No); per Crystran; printed as 1.75449 -	690form: single crystal (EFG); temperature: not stated; orientation: not stated; per Kyocera 480 to 895form: single crystal substrate or wafer; temperature: not stated; per Valley Design

Bending (flexural) strength depends on the test, the surface and the temper, so the records are listed, not ranked. Refractive index is shown with the wavelength it was measured at. Poisson's ratio is the ratio of sideways contraction to stretch under load (dimensionless).

What are metallic glass, glass-ceramic and organic glass, and are they glass?

Metallic glass is an alloy cooled fast enough that it does not crystallise, so it has no crystal structure but is a metal, not transparent glass. ZERODUR is a glass-ceramic with nanocrystals in a glass phase. PMMA and CR-39 are polymers sold as organic glass. Sapphire is a single crystal. Our data holds records for each, with gaps listed below.

What is metallic glass, and what is it not?

Metallic glass is an alloy with an amorphous (non-crystalline) structure. The Metglas ribbons in our data are made for transformer cores and brazing; the profile records density, stiffness, expansion and hardness for named grades, and Poisson's ratio for none of them. It is not transparent, and it is not a drop-in replacement for window or lens glass (general engineering knowledge, not in our data).

Metallic glass records by named grade or alloy. Each cell is one source's record with its own condition.
Grade or alloy	Density, g/cm3	Young's modulus, GPa	Thermal expansion, ×10⁻⁶ per K	Tensile strength, MPa	Yield strength, MPa	Vickers hardness, HV	Glass transition, °C
Metglas 2605SA1	7.18note: the datasheet says these numbers are not guaranteed; per Metglas	110note: the datasheet says these numbers are not guaranteed; per Metglas	7.6temperature range: 30 to 300 °C; per Metglas; printed as 7.6 x10-6/°C	2000note: printed as 2,000 N/mm2; the datasheet says these numbers are not guaranteed; per Metglas; printed as 2000 N/mm2	not found in any source we hold	900load: 50 g (Hv-50 g load as printed); per Metglas	not found in any source we hold
Metglas 2714A cobalt-based ribbon	7.59per Metglas	100 to 110per Metglas	12.7per Metglas; printed as 12.7 ppm/°C	1000 to 2000per Metglas; printed as 1 to 2 GPa	not found in any source we hold	960load: 50 g (as printed); per Metglas	not found in any source we hold
Vitreloy, as titled on the slide (Zr-Ti-Ni-Cu-Be bulk metallic glass)	not found in any source we hold	not found in any source we hold	not found in any source we hold	not found in any source we hold	1986test: tension, true stress, 0.1 MPa hydrostatic pressure; strain: f = 0 %; note: the slide gives the value as yield or…; per Lindsay Greer, Bulk	not found in any source we hold	not found in any source we hold
Zr51Al14.2Ni15.9Cu18.9 (at %), research alloy from the Zr-Al-Ni-Cu series, not Vitreloy	not found in any source we hold	not found in any source we hold	not found in any source we hold	not found in any source we hold	2073note: column sigma y in Table 1, printed without unit suffix; MPa from the column header; per A series of	not found in any source we hold	not found in any source we hold
Zr51Al14.2Ni15.9Cu18.9 (at %), research alloy, not Vitreloy	not found in any source we hold	not found in any source we hold	not found in any source we hold	not found in any source we hold	not found in any source we hold	not found in any source we hold	452.6heating rate: 30 K/min (table caption); per A series of; printed as 725.7 K

What is ZERODUR, and how does it differ from glass?

ZERODUR is a lithium aluminium silicon oxide glass-ceramic from SCHOTT. It prints a Young's modulus of 90.3 GPa at 20 °C (SCHOTT) and a maximum application temperature of 600 °C (SCHOTT). Its mean expansion is supplied as 0 ± 0.1 ×10⁻⁶ per K for Expansion Class 2 and 0 ± 0.007 ×10⁻⁶ per K for Class 0 Extreme. Corning ULE 7972, a glass, is supplied at 0 ± 0.03 ×10⁻⁶ per K (Corning).

Are PMMA and CR-39 glass?

PMMA and CR-39 are polymers used where glass would be too heavy or too fragile (general engineering knowledge, not in our data). PMMA (PLEXIGLAS GS) prints a density of 1.19 g/cm3 at 23 degC (PLEXIGLAS datasheet), a modulus of 3.3 GPa at 23 degC (PLEXIGLAS datasheet) and an expansion of 70 ×10⁻⁶ per K over 0 to 50 degC (PLEXIGLAS datasheet). CR-39 prints a density of 1.317 g/cm3 temperature not stated (NASA) and an expansion of 117 ×10⁻⁶ per K over not printed (a US patent); its modulus is not found in any source we hold.

Is sapphire a glass?

Sapphire is a single crystal of alpha-alumina, not a glass. The two suppliers differ: Crystran prints a Young's modulus of 470 GPa temperature not stated (Kyocera) and Kyocera 470 GPa temperature not stated (Kyocera), so the sapphire tiles in the meter are shown for each source separately. With an expansion of 7.7 ×10⁻⁶ per K over 40 to 400 °C (Kyocera) (Kyocera) it would load fastest of all tiles on this page.

Which properties of glass are missing from our data?

The database does not hold a bending strength for 10 of the 14 glasses on this page, and 4 of the 15 meter tiles lack an input for the stress estimate. The page therefore cannot say at which temperature step any given glass breaks. The gaps are listed below.

Bending strength. Found for Borosilicate glass, Soda-lime glass, Aluminosilicate glass, SCHOTT Xensation Core and Sapphire, Kyocera EFG single crystal. Not found in any source we hold for Fused silica, Aluminosilicate glass, Corning EAGLE XG, Aluminosilicate glass, Corning Gorilla Glass 2, Corning ULE 7972 titania-silicate glass, ZERODUR glass-ceramic, Expansion Class 2, AGY S-2 Glass fibre, Metglas 2605SA1 metallic glass, Metglas 2714A metallic glass, Poly(allyl diglycol carbonate), ADC (CR-39) and Poly(methyl methacrylate), PMMA (PLEXIGLAS GS). For that reason the meter shows no strength mark on those gauges.
Inputs of the stress estimate. Metglas 2605SA1 metallic glass (Poisson's ratio), Metglas 2714A metallic glass (Poisson's ratio), Poly(allyl diglycol carbonate), ADC (CR-39) (elastic modulus and Poisson's ratio) and Poly(methyl methacrylate), PMMA (PLEXIGLAS GS) (Poisson's ratio) have no estimate because an input is not found in any source we hold.
Annealing and strain points. An annealing point is printed for 8 of 14 entries and a strain point for 6. Not found for the annealing point: ZERODUR glass-ceramic, Expansion Class 2, Metglas 2605SA1 metallic glass, Metglas 2714A metallic glass, Poly(allyl diglycol carbonate), ADC (CR-39), Poly(methyl methacrylate), PMMA (PLEXIGLAS GS) and Sapphire (single-crystal alpha-alumina), all records.
Glass transition. Printed for 4 of 14 entries; the rest are not found in any source we hold, which is too few to compare.
Thermal conductivity and specific heat. Thermal conductivity is not found for Aluminosilicate glass, Corning Gorilla Glass 2, Aluminosilicate glass, SCHOTT Xensation Core, Metglas 2605SA1 metallic glass, Metglas 2714A metallic glass and Poly(allyl diglycol carbonate), ADC (CR-39); specific heat is not found for Aluminosilicate glass, Corning Gorilla Glass 2, Aluminosilicate glass, SCHOTT Xensation Core, Metglas 2605SA1 metallic glass, Metglas 2714A metallic glass, Poly(allyl diglycol carbonate), ADC (CR-39) and Poly(methyl methacrylate), PMMA (PLEXIGLAS GS).
Cover glass. The profile holds Corning Gorilla Glass 2, an alkali aluminosilicate cover glass, and SCHOTT Xensation Core. A bending strength for chemically strengthened Gorilla Glass 2 is not found in any source we hold; Xensation Core prints a lower bound after chemical strengthening, which the meter shows as a bar above the gauge range.
No break prediction. The data holds no thickness, edge, surface-finish or cooling-rate condition for the estimate, so the meter cannot say at which step a part cracks.

What do people ask about the properties of glass?

What is the thermal conductivity of borosilicate glass?

Borosilicate glass has a thermal conductivity of 1.2 W/(m·K) at 90 °C (SCHOTT) for SCHOTT BOROFLOAT 33. Fused silica prints 1.4 W/(m·K) temperature not stated (PMOptics) and 1.3 W/(m·K) at 25 °C (Corning), and soda-lime glass prints 0.937 W/(m·K) at 75 °F (Pilkington). The temperatures and sources differ, so the values are listed and not averaged.

What is the melting point of borosilicate glass?

Borosilicate glass softens over a range instead of melting at one temperature (general engineering knowledge, not in our data). SCHOTT prints a softening point of 815 °C, an annealing point of 560 °C and a long-term maximum operating temperature of 450 °C.

What is the coefficient of thermal expansion of glass?

It depends on the glass. Borosilicate glass prints 3.25 ×10⁻⁶ per K over 20 to 300 °C (SCHOTT), soda-lime glass 8.3 ×10⁻⁶ per K over 75 to 575 °F (Pilkington) and fused silica 0.55 ×10⁻⁶ per K at 20 °C to 320 °C (PMOptics). ZERODUR Expansion Class 0 Extreme is supplied at 0 ± 0.007 ×10⁻⁶ per K over 0 °C to 50 °C (SCHOTT). Wikipedia prints 9.5 for soda-lime glass, so sources differ.

What is the density of glass?

Borosilicate glass prints 2.23 g/cm3 at 25 °C (SCHOTT), fused silica 2.2 g/cm3 temperature not stated (PMOptics) and soda-lime glass 2.5 g/cm3 at 18 °C (Continental Trade). Aluminosilicate glass prints 2.42 g/cm3 (Corning) for Corning Gorilla Glass 2. Most of the glasses on this page fall between 2 and 3 g/cm3; the full list with conditions is in the density table.

Is borosilicate glass stronger than soda-lime glass?

Our data cannot rank them. SCHOTT prints 25 MPa bending strength for borosilicate glass under normal conditions (DIN 52 292) and Pilkington prints 41 MPa mean modulus of rupture for annealed soda-lime glass; the tests differ. What the data does show is lower thermal stress per kelvin in borosilicate glass: 0.26 MPa against 0.766 MPa.

Is metallic glass really glass?

Metallic glass is glass in structure, not in appearance: it is an alloy with a disordered atomic arrangement, made by cooling so fast that it does not crystallise. Metglas 2605SA1 is an iron-based ribbon with 110 GPa (Metglas) Young's modulus and 900 HV (Metglas) Vickers hardness. It is opaque, and its Poisson's ratio is not found in any source we hold.

What are the properties of aluminosilicate glass?

Aluminosilicate glass is a silica network with alumina and alkali or alkaline-earth oxides. Corning EAGLE XG prints 73.6 GPa (Corning) Young's modulus and 3.17 ×10⁻⁶ per K over 0 to 300 C (Corning); Corning Gorilla Glass 2 prints 71.5 GPa (Corning) and 8.14 ×10⁻⁶ per K over 0 to 300 C (Corning). Bending strength of Gorilla Glass 2 is not found in any source we hold.

Which glass has the lowest thermal expansion?

ZERODUR Expansion Class 0 Extreme is supplied at 0 ± 0.007 ×10⁻⁶ per K over 0 °C to 50 °C (SCHOTT), and Corning ULE 7972 at 0 ± 0.03 ×10⁻⁶ per K over 5 to 35 °C (Corning). Fused silica prints 0.55 ×10⁻⁶ per K at 20 °C to 320 °C (PMOptics). The ZERODUR and ULE figures are supplied tolerances around zero, so the real value may sit a little either side of zero.

Where can I read more on these materials?

How was this page made?

Each glass is a profile in the Space Mushroom database, drafted by AI assistants from cited pages and checked by a script that finds each value in the source it cites. This page reads the profiles when it is built, so a corrected record changes the page. Data checked 2 November 2026. Every value links to its profile.

Data checked 2 November 2026. Next review when a profile changes.

How to cite: Space Mushroom, "Properties of glass: borosilicate, fused silica, soda-lime", https://spacemushroom.com/articles/properties-of-glass/, data checked 2 November 2026.

How much stress does a sudden temperature change put on glass?

Corning ULE 7972 titania-silicate glass

Bending strengths printed in the profiles, and the step at which the estimate reaches each

The same estimate as a table

What is glass made of, and how do the types differ?

What are the density, thermal expansion and thermal conductivity of glass?

Why does borosilicate glass resist thermal shock?

What do the suppliers print as safe temperature steps?

What is the melting point of borosilicate glass?

How stiff and how strong is glass?

What are metallic glass, glass-ceramic and organic glass, and are they glass?

What is metallic glass, and what is it not?

What is ZERODUR, and how does it differ from glass?

Are PMMA and CR-39 glass?

Is sapphire a glass?

Which properties of glass are missing from our data?

What do people ask about the properties of glass?

What is the thermal conductivity of borosilicate glass?

What is the melting point of borosilicate glass?

What is the coefficient of thermal expansion of glass?

What is the density of glass?

Is borosilicate glass stronger than soda-lime glass?

Is metallic glass really glass?

What are the properties of aluminosilicate glass?

Which glass has the lowest thermal expansion?

Where can I read more on these materials?

How was this page made?